content: /*
   * Copyright 2011-2016 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package ix;
  
  import java.util.Iterator;
  
  final class IxRetain<T> extends IxSource<T, T> {
  
      final IxPredicate<? super T> predicate;
  
      IxRetain(Iterable<T> source, IxPredicate<? super T> predicate) {
          super(source);
          this.predicate = predicate;
      }
  
      @Override
      public Iterator<T> iterator() {
          return new RetainIterator<T>(source.iterator(), predicate);
      }
  
      static final class RetainIterator<T> extends IxSourceIterator<T, T> {
          final IxPredicate<? super T> predicate;
  
          RetainIterator(Iterator<T> it, IxPredicate<? super T> predicate) {
              super(it);
              this.predicate = predicate;
          }
  
          @Override
          protected boolean moveNext() {
  
              for (;;) {
                  if (!it.hasNext()) {
                      done = true;
                      return false;
                  }
  
                  T v = it.next();
  
                  if (predicate.test(v)) {
                      value = v;
                      hasValue = true;
                      return true;
                  } else {
                      it.remove();
                  }
              }
          }
  
          @Override
          public void remove() {
              it.remove();
          }
      }
  
  }
  